Electric heating device.



No. 888,381. PATENTED MAY 19, 1908.

I W. S. ANDREWS '& H. J. MAUGER.

ELECTRIC HEATING DEVICE.

APPLIOA'IION'I'ILEI) SEPT.18. 1907.

Fig. l.

Witnesses: In ventors'.

' William SJTndrews,

s Henry J. mau er,- I I by yaw,

' UNITED" STATES PATENT OFFICE.

WILLIAM s. ANDREWS AND-HENRY .1. MAUGER, or SCHENECTADY', NEW YORK, ASSIGNORS 'ro GENERAL ELECTRIC COMPANY, A CORPORATION on NEW YORK.

ELECTRIC IIEATING DEVICE.

\ To all whom it may concern:

have invented certain new and useful Improvements in Electric Heating Devices, of which the following is a specification.

This invention relates to electric heating devices and'has for its object the provision of means whereby the excessive heating of a device of this character is prevented'in a reliable, safe and efiicient manner.

In the use. of electric heaters it is not-uncommon to include a switch which will automatically open before a certain destructive temperature is reached and will again close when the temperature is reduced. Thermostat switches of this character are not always reliable in that they. are liable to get out of order and fail to open the circuit at the desired temperature. In such devices as heating pads and the like, it as exceedingly important that the safety device be thorough y reliable as these devices are frequently used in positions where, if overheated, the results are apt to be exceedingll y serious. n

e object of our invention isto provlde means whereby the circuit will positively open u on the occurrence of excessive heativr yg an will not again automatically close.

e arrange this form of cut-out in connection with a thermostat which ordinarily will open and close thecircuit upon rearranged variations of temperatures. Ii this switch fails at any time to open the oilcuit, the cut-out will be sure to operate to permanently open the circuit.

In the accompanying drawing, we have shown, forpur oses of illustration, our invention applie to aheatingpad.

In these drawings Figure 1 is a plan view of a heating padiequipped with ourimprovemerits, certain portions being broken away to show the construction; Fig. 2 is a view of the cut-out; Fi 3 is a longitudinal section of the same; and l ig. 4 is a diagram of circuits.

' Referring to the drawings, 10 is a heating 'padfwhich ma ,beof some well known construction, as, 01'. instance, that shown in the patent of .Soden, 473,133, A ril 19,, 1892.- .he particular construction 0 this heating Specification of Letters Patent. Application filed September 18, 1907. Serial No. 393,471.

however,

Patented May 19, 1908.

pad forms no part of our invention, although we prefer to use a form in which our rotective devices may be easily embedde or concealed from View and not in any danger of being tampered with. Secured within the heating pad 1n some Way, as, for instance, b

sewing it in place, is a thermostatic switc 11. This switch may be of any well-known construction, such, for instance, as that in the patent to Meek, No. 568,451, September 29, 1896. This thermostat is in thermal relation with the heatingconductors so that it will be affected by .the variations in temperature of the pad itself. This thermostat is in series with the heater and when it opens will interrupt the heating current. with this thermostatic switch is a cut-out 12. This cut-out is arranged so as to automatically and permanently open the circuit upon a prearranged rise in'temperature and consists of an insulating support 13, having a slotted central portion 14. Secured at opposite ends of the support are spring contact strips 15 and 16, which may be of any spring metal, preferably, .a good conducting material, as spring brass, although other .materials maybe employed if desired. These strips may be arran ed,by bending or otherwise so that the en s are apart as shown in the dotted lines in Fig. 3. The ends are then brought together and secured in place by fusiblemetal 17, such as lead, solder or some easily fusible metal. The strips are provided with terminals .18 and 19 for connecting in the inner circuit. also secured within the heating pad so as to be in good thermal relation therewith and This cut-out is In series responsive to changes of temperature. Ordinarily, when the heatingpad becomes egtcessively hot so as toendanger it, the thermostatic switch willopen the circuit and agam close it when the temperature is reduced.

If, however, this fails to operate, the fusible 3 set forth in the annexed claims.

What we claim as new and desire to secure by Letters Patent of the United States, is,

1. The combination withan electric heater of a thermostatic switch in circuit therewith and afusible cut-out in series with said switch and in thermal relation with the heater.

2. The combination with an electric heater of a thermostatic switch in series therewith and a cut-out in series with said switch and in thermal relation with the heater, said cut out being biased to 0 en position and normally; closed by a fusi le metal.

3. The combination with an electric heater of a thermostatic switch and a'fusible cut-out in series with each other in the heater circuit, said devices being in thermalrelation with the heater and operated independently of the amount of current flowing.

4. The combination with an electric heater of a cut-out in series therewith comprising contacts spring ressed toward an 0 en position and norina y closed by a fusible metal.

' '5. The combination with an electric heater of a cut-out in circuit therewith comprising spring contact strips arranged in o en position and normally s rung to a close position and sealed by a fusible metal. 7 p

In witness whereof, we have hereunto set our hands this 16th day of September, 1907 WILLIAM s. ANDREWS. HENRY J. MAUGER. I

'Witnesses:

BENJAMIN B. HULL, MARGARET E. WOOLLEY. 

